"He is a great footballer with a huge amount of pace and skill, and he is an extremely exciting player. I am delighted to have him on board.''

Tiesi added: ''I have very much enjoyed my time at London Irish, and feel that I have truly developed as a player. I think that it is time for the next step in my career, and I am excited about the move.

"Harlequins have offered me a real opportunity for a new and fresh challenge, and I am looking forward to working with Dean Richards and his team.''